Free Vibrations of Laminated Beams Containing a Delamination

A study is made on the effect of delamination on the natural vibration characteristics of laminated beams. Free vibration of the simply supported beam with a delamination of arbitrary size and location is analyzed on the basis of the Euler beam theory. Axial forces induced by bending in the parts of the beam above and below the delamination are determined by regarding the cracked part as two lapped beams hinged at both ends. Numerical results for natural frequencies, mode shapes and normal contact pressure between the delaminated layers are presented for the first four modes. Experiments are also conducted. It is shown that the analytical solutions for natural frequencies agree well with experimental results